Plastics film, use of dyestuffs therein and process for testing the authenticity of packaged goods

Abstract

A dyestuff capable of undergoing a clearly visible colour change when contacted with a color-developing material is dispersed in the body of a plastics film and used in the identification of goods. The film can be used for packaging of the goods or as a label or seal affixed to the goods. When testing the authenticity of packaging goods, the plastics film is marked with the color-developing chemical to produce a colored mark on the package. The dyestuff is preferably a latent dyestuff which is colorless and invisible to the eye under ambient conditions for use of the film but which forms a clearly visible color when contacted with the color-developing material.

What is claimed is:  
     
       1. A process for testing the authenticity of packaged goods, comprising the steps of: 
       packaging the goods in packaging material including an outer layer of plastics film over at least a part of a surface area of the packaged good, the plastics film having a dyestuff dispersed in the body of the plastics film, said dyestuff undergoing a clearly visible colour change when contacted with a colour-developing chemical, and  
       applying to the outer layer of the packaging material, which is comprised of the plastics film, said colour-developing chemical to produce a coloured marked area thereon to authenticate the packaged good.  
     
     
       2. The process according to  claim 1 , wherein the said plastics film forms the outermost layer of laminated packaging material. 
     
     
       3. The process according to  claim 1 , wherein the plastics film forms a seal which has to be broken to open the package. 
     
     
       4. The process according to  claim 1 , further comprising the step of contacting said marked area with a chemical which reacts with the dyestuff to change said marked area back to its original colour so that the marked area is indistinguishable from the rest of the film. 
     
     
       5. The process according to  claim 1 , wherein the dyestuff dispersed in the body of the plastics film is a latent dyestuff which is colourless and invisible to the eye under ambient conditions for use of the film. 
     
     
       6. A plastics film and marker combination for identifying packaged goods to which the plastics film is applied over at least a part of a surface area of the packaged good, comprising: 
       a plastics film having a dyestuff dispersed in a body of the plastics film, the dyestuff undergoing a clearly visible colour change when contacted with a colour-developing chemical, and  
       means for marking the plastics film with said colour-developing chemical to authenticate the identification of the packaged good.  
     
     
       7. The plastics film and marker combination according to  claim 6 , wherein the dyestuff dispersed in the body of the plastics film is a latent dyestuff which is colourless and invisible to the eye under ambient conditions for use of the film. 
     
     
       8. The plastics film and marker combination according to  claim 6 , wherein the plastics film is an outer layer of a packaging material for packaging goods. 
     
     
       9. The plastics film and marker combination according to  claim 6 , wherein the plastics film is an outer layer of a laminated packaging material for packaging goods. 
     
     
       10. The plastics film and marker combination according to  claim 6 , wherein the plastics film comprises a seal for packaged goods. 
     
     
       11. The plastics film and marker combination according to  claim 6 , wherein the plastics film is a label for packaged goods. 
     
     
       12. The plastics film and marker combination according to  claim 6 , wherein the colour-developing chemical used to mark the plastics film is in solution in a solvent which does not damage the plastics film. 
     
     
       13. The plastics film and marker combination according to  claim 12 , wherein said means for marking is a marker pen. 
     
     
       14. The plastics film and marker combination according to  claim 13 , wherein said marker pen is a fibre-tipped pen. 
     
     
       15. The plastics film and marker combination according to  claim 6 , further comprising means for contacting a marked area of the plastic film with a chemical which reacts with the dyestuff to change the marked area back to its original colour so that the marked area is distinguishable from the rest of the plastics film.